Telegraph system



Jan. 29, 1935. E. H. JOLLEY El AL TELEGRAPH SYSTEM Filed Jan. 26, 1935 Patented Jan. 29, I935 j UNITED STATES Ernest Harris 'Jolley and olin Martin, Harrow,.England,- assignors, to Auto-.1

matic Electric Company Limit d, Liverpoiol;'

England, aBritish company Application January 26," 1933,?S8hifiI- N0, 653353 6 i t 'In Great Britain February 3,;1932'5 v 7' Claims; (011178 531) v The present invention relates to electric telefive for 'determinin graph and like systems and is more particularly signal. i It willbe resented by elements of, different wave forms, for are known as teleprinters in which the operation 5 instance, systems in which the elements areof of a keyboard similar to' that of a typewriter difierent length composed of varying numbers produces atyped-messageat' both the sending of units. The invention moreover is more par'-' and receiving ends. 1 ticularly ooncerned'with systems of the so-called Referring now to Fig. 1; signal currents inoom start-stop type in which the necessity for acingover'leads 1 and Z aref'ed to the polarized curate synchronism between the transmitting and receiving relay-3 which on energizingwhen the receiving equipment is avoided by arranging that current *over the line is reversedproduoes operaeach signal is preceded by a start impulse and tion of the tongue 43 This thereuponcompletes followed by a op m l e o that as the error an operating circuit ror'a polarized is non-cumulative accurate correspondence be- 5 whjch'jsladapted a fhtween the speeds of the equipment at the transmitting andreceiving e'nqlis not necessary.

q ei s e n m s o Particularly.- sented by 7 The "regenerating' apparatus in-' overv underground cables-the difierent elements I 1 I i tend to.become distorted with respectftotim'e on eludes "Segmented" wh'lch preferably' m accou'ntof the electrical characteristics of the g gf gf g v 1T lX y"a dJuSt- 2 ge gir g e i ge n e? -93 clutch mechanism fwith ashait' driven *rr m; the e 0 J Presen mven Ion 1S 0 prom. we, motor 8 by means of suitablege'aring 9 ata speed simple and efiec-tltven means whereby 5411 d slightlyin exce'ss of thatbf'theteleprinter trans torted signals may be regenerated and restored i tions or beingcaused to operate'iautomatic type signals beforeregeneration-eat great toenable e e We p s. i eat m t the so the type printing or other mechanism to be satisumts 90mm 5 the signal normally-prevented factb'rfly operated 2 from turning, but onthe operation of the'arm 11 According to one feature of the invention in by-thg'engrgizafion 9 E mgnt-the latch-whigh a telegraph system of the start-stop typeyregene g I eration of signa eif'ectedby arranging that "a lowed, to 93 599; -9P- X means-Of h 35 predetermined small portion of each signal unit clutc-nrmechamsm' ,P9 T 9n the operates a transmitter from which a re-transmit e tl d 'respectwelyl bathe r 14 an ting relay is controlled in such a manner that it 15 W 33?! ar UPP- mF- aw f m i only alters the position of its tongue inresponse t9 i most it l 3 9 9 slgnal currentin the control circuit. F t i rl t i d' The 9 5 v p n to \the According to another feature ofthe invention end .i=. f he tren te .;w e the the incoming signals operate an electromagnet m fI 5' extends b W Y 'lTesistanile 1'8 'ahd which on energization releases a latch to permit o de e te ih n fl m fye ap m r a segmented disc to make one revolution and also Th r nd f fi lg q ner 1S conngctfid' operates a transmitter from Which a. circuitis' o he polar ze n m tme f @133, 2D. the completed over the conducting segments ofthe 0 3 of Wh servfisto at e a r disc 'f01' operatinga re-transnnttingtrelay; e o in lin lI D S E ead s 22 and 23 The invention'will be better {understood from Ash s lr y en m nt o 'thefd nd the following descriptionof twqmethm o f car 3 a e relatively movable *and the' adjustment rying it into effect which shouldbe taken" in conwill normally be such that 'ionflya comparatively 50 junction with the accompanyingdrawing comsmall portion'of the conductingfsegments will prising Figs. 1 and 2. The invention is shown overlap. This will mean thatithe circuit'irom applied to a start-stop telegraph system arranged brush 14 to bru sh 1 5 is only completed for a very in the usual manner so'that each signal com- 'smallportionof thetimejrepresented by ai'signal 5 5 prises seven units, one forstart, on e for stog g d This timemust, however v h 'gre'at an to its alternate contact and an operating circuit is completed for magnet 5 which thereupon releases the latch so the correcting disc contact '7. It is arranged that 'a cer'tain -delay takes place in the operation of contact 7 in order" to permit the discs to attainithe requlsitespeed before the brushes be seen that for a and 15. It will be appreciated, ,however,, that if the circuit from brusnldextended directly to relay 20 an impulse wouldbe transmitted to the relay each time the brushes passedover-a conducting segmentand this wouldlcause chattering of the relay which is clearly objectionable. -What is required is that each time a reversal of current takes place in the incomingline circuit the tongue of relay 20 shouldbe positively reversed and that no further current should then flow until operation in the other direction s to takeplace. It is for fulfilling this requirement that the special.

arrangement shown in Fig. 115 employed. As

i previously mentioned, thecircuit for the primary of transformer 17 includes resistance 18 and condenser 19" andthe, values of fthese'components are so chosen that they ram; an; oscillatory circuit with. ccnsiaerame dam ing; and of such period that the first pl'llsei dqciiples Substantially the same time as that during iwhic h the. signal 18 repeated over "brushes Q14 and '15'. This: means that condenser 19v will' besubstantially fully chargedwhile the circuit completed respect of "one signal im'it'but thatithere'is noitime for cur'rent'to flow in the reverse. direction. Moreover, the current flow islzerofatit nstant that the brushes are" leaving the conducting segment and this .isiofpra'ctical mpcr a eesm spark quenchdevlces cannot be employed. If

the succeeding signalunit isof the same sign no further change takes place sincej ndease 19 is lfully charged. When the current mm incoming line is reversed, however, transmitter contact. 7 is operated and when the connection between brushes 14 and is established a flow of current takes placeto charge condenser 19in the opposite direction. "This current flowing through" the primary of transformer IFTinduc es a current in the secondary which'eifects the operation ofrelay 20'and'thu retransmit s. the signals over the outgoing line. 'It be mentioned {that with. a disc speed and segment length'such thatbrushes 14 and 15 are"connected together .ter 3" milliseconds a value for resistance 18 of 2000 ohms and a value for condenser 19 of 0.5. niicrofarads have given good results. .These valuesare of course to some extent dependent on the-value of the inductancewo f "theprimary of the transformer '7 which is convenientlyan "ordinary telephone line transformer.

fIn certain jcircu1nstances it maybe necessary to bring 'thejdisc 'to' rest in suchia position that the brushes rema contact with the last conducting segment-W111 order thatwhen the transas to permit the shaft carrying 12, 13 te-rnake onerevolution and at the same time operates the 'tra'ri's'rnitten become effective; ItwillmoW- short portion of each signal unit depending on the relative adjustment of the" discs, a circuit will'be completed over. 14,

mitter changes over on receipt of the start signal for the next letter the re-transmitting relay shall not be immediately operated, it may be arranged that the connection of the positive pole of the battery associated with the transmitter shall only be connected when the disc'is in motion and disconnected when the disc is. at rest.v

Consideration will now be given to the alternative arrangement shown in Fig. 2. In this case the retransmitting relay instead of being strongly 'pol'ariz'ed'i'sprovided with a bias winding and use is made ofa thermionic valve for ensuring that impulses forhoperating the relay shall only be sent' -when 'the signal currents change sign. In this case owing to the almost complete lack of inertia of thevalve, the portion of the signal units usedifon regenerating may be even smaller and thus a greater degree of distortion can be satisfactorily corrected.

The two relatively movable halves of the segmented disc represented in Fig. 2 by 33 and 34 are wiped over by the brushes 35 and 36 and are driven in the same manner as in the, arrangement ofiFig. 1', control by the incoming signals being alsosimilar. The operation of the delayed transmitter contact31, however, inthis 'c'ase connects up'oneor other pole of the battery 32 to brush 36. The valve' 39 is provided with the usual grid bias battery 40, filament battery 41 and anode battery 42 and the relay 43 provided with contact 44 has a bias winding which with the circuit shown receives current continuously from battery 42 over resistance 45. The values of the grid bias applied from battery by way of the grid leak 38 is such that normally practically no current flows in the anode circuit and tongue 44 is held in the position shown by current flow through the bias winding. When the transmitter contaot31 is operated, however, the positive pole of battery 32 is connected up for a short interval over brushes35 and 36 and potential thus applied tothe grid of the valve permits anode current to flow and also {charges up condenser 37. The current 'flow through .the operating winding of relay 43 nowfvercomes theefiect of the bias winding and-causestongue 44 to engage its alternate contact to retransmit the. signal over the outgoing line. The condenser 3''! is necessary to maintain the grid potential during the portion of the signal unit .when'battery 32 is not connected up and the'grid leak 38 is of such value that no appreciable discharge of condenser 37 will take place while the brush is passing between two of the conducting segments but the condenser will not hold its charge for an extended period. When the transmitter contact31 again returns to the position shown, thecondenser 3'7 is short-circuited, the grid potential isreduced and the anode current ceases to'fiow.

It should be mentioned that with a modified form of clutchgiving sufficiently rapid starting of the disc it would be feasibleto dispense with the additional transmitter contact '7 and to connect brush 14 direct to the tongue 4 of the receiving relay 3. The useof transmitter '7 com trolled by magnet 5 to give a delayed action is only desirable to overcome possible difficulties due to theslowstarting of released by member Itwill of course 11 be'understood that retransmitting relay 20 may be arranged to transmit the disc when the latch is transmitting relay.

3. In a start-stop telegraph system, a regenerative repeater a transformer, the retransmitted impulses fully charging said condenser.

4. In a start-stop telegraph system, a regenmented discs,

length of retransmitted impulses over said brushes.

to'in turn operate said relay.

7. A system such as claimed in claim 6 having retransmission of a signal to prevent distortion thereof.

' ERNEST H. J OLLEY. JOHN A. S. MARTIN. 

